The present invention relates to an exterior sideview mirror assembly suitable for mounting on a vehicle and, more particularly, to an exterior sideview mirror assembly which incorporates a skullcap or shell or scalp to provide a decorative appearance to the assembly.
Conventionally, vehicles are equipped with at least a driver""s side exterior mirror assembly, which is mounted either to the body of the vehicle or in the door frame of the vehicle. More often, vehicles are also equipped with a passenger side exterior mirror assembly which is typically mounted to the opposite side of the vehicle in a similar fashion to the driver""s side exterior mirror assembly. The trend in exterior rearview mirror assemblies has been to form an exterior mirror assembly which exhibits better aerodynamic characteristics and, further, which has an aesthetic appearance, preferably with the exterior mirror assembly being decorated to have a high gloss and/or to match the vehicle body paint.
However, more recently in an attempt to reduce the cost of manufacturing such assemblies, a composite assembly has been developed which includes a frame and a shell or skullcap or scalp, which is mounted to the frame, for example by snap connectors. The frame is formed from an engineering plastic, typically a reinforced engineering plastic, such as reinforced nylon or the like. The shell or skullcap is also formed from a plastic substrate which is then painted to match the vehicle body color. The structural capacity of the housing is provided by the frame, with the shell providing a decorative covering over the frame so that the housing generally matches the vehicle body. As a result, however, the wind noise of the side exterior mirror assembly can be increased. This wind noise is generated such as by the space between the decorative shell and the frame of the mirror assembly.
Various attempts have been made to minimize and/or eliminate the wind noise. One approach is to eliminate the space between the decorative shell and the frame. However, in order to eliminate the space, the tolerances on the respective parts must be extremely tight, which adds the expense of the sideview exterior mirror assembly fabrication. Another approach is to alter the surface topology of the decorative shell to separate the air flow over the side exterior mirror assembly, which reduces the noise of the wind flow. For example, in German Patent 4,039,484 to Bayerische Motoren Werke AG, a plurality of raised portions or xe2x80x9cbumpsxe2x80x9d are provided to separate the air flow over the housing. However, these raised portions are not aesthetically pleasing to some automobile manufacturers and, further, project above the assembly and create a distraction to the driver. In addition, it has been found that when a discontinuity is introduced into the substrate of the skullcap (such as when it is molded in a molding tool), that the noise reduction advantages of such a surface molded discontinuity is reduced drastically by the painting process which follows since the painting process alters the surface topology of the substrate and, rather than following the surface discontinuities, at least partially fills in the discontinuities.
Consequently, there is a need for an exterior rearview mirror assembly which incorporates a decorative skullcap that exhibits reduced noise while retaining the aesthetic appearance of the mirror assembly.
The present invention provides a sideview mirror assembly which incorporates a decorative shell, more specifically a colored shell, and most preferably of a color that matches the color of the vehicle body. The decorative shell includes a surface discontinuity to reduce the wind noise of the sideview mirror assembly. In order to maintain the geometry of the surface discontinuity, a composite decorative shell is provided which is formed from a shell substrate and a decorative film that is molded with the shell substrate so as to substantially maintain the geometry, such as sharpness, of the discontinuity.
In one form of the invention, a vehicular sideview exterior mirror assembly includes a body which is adapted for mounting to a vehicle, with the body having a mirror case wall defining a cavity and an opening for facing rearward of the vehicle. The reflective element is housed in the cavity and positioned in the opening for rearward viewing of the vehicle. The body includes a forward facing portion which is decorated and which forms an exterior surface discontinuity to reduce the wind noise of the vehicle sideview exterior mirror assembly. The forward facing portion is decorated by a decorative film which is molded with the forward facing portion of the body.
In one form, the surface discontinuity comprises a ridge. For example, the ridge is preferably substantially continuous having a pair of terminal ends, which may be tapered. In other aspects, the body includes a decorative shell mounted therein which defines a groove between the shell and the body. The ridge is preferably spaced from the groove. In a further aspect, the ridge has a longitudinal extent which is generally parallel with the groove. In other aspects, the body includes a perimeter edge which extends around the opening, with the groove being spaced a groove distance from the perimeter edge of the case wall, and the ridge being spaced at least a ridge distance from the groove, wherein the ridge distance is at least equal to the groove distance.
In yet further aspects, the shell and the body define a substantially continuous forward facing exterior surface. The ridge preferably forms a step in the substantially continuous surface. For example, the step may have a maximum height in a range of 0.25 to 5.0 mm, more preferably in a range of 0.5 to 4.0 mm and, most preferably a maximum height in a range of 1.0 mm to 2.0 mm.
In another form of the invention, a vehicular sideview exterior mirror assembly includes a reflective element and a mirror case which has a mirror case wall defining a cavity and an opening for facing rearward of the vehicle. The mirror case is adapted to mount to the vehicle and houses the reflective element in the mirror case cavity in the opening for rearward viewing of the vehicle. A shell member, which is adapted to secure to the case wall, is positioned exteriorly over a forward facing portion of the case wall. The shell member has an exterior decorative film molded therewith to enhance the aesthetic appearance of the vehicular sideview exterior mirror assembly and which forms an exterior surface discontinuity to reduce the wind noise of the mirror assembly.
In one aspect, the surface discontinuity comprises a ridge. Preferably, the ridge has a longitudinal extent which extends along at least a portion of a lateral extent of the mirror case. Further, the shell member and the case wall define a substantially continuous exterior surface, with the ridge defining a step in the substantially continuous exterior surface.
In yet another form of the invention, a vehicular sideview exterior mirror composite shell member for a vehicular sideview exterior mirror assembly is formed by providing a decorative film substrate having an inner facing surface and an outer facing surface for facing exteriorly of the mirror assembly when the composite shell member is mounted to the mirror assembly. The decorative film is placed in a molding apparatus which includes a mold cavity having a discontinuity formed therein with an edge definition. The decorative film is placed in the mold cavity, and a polymer resin is injected into the mold cavity over the film such that the film and polymer resin conform to the mold cavity and further conform to the edge definition of the discontinuity such that the outer facing surface of the film forms a surface discontinuity for reducing the wind noise characteristics of the composite shell.
In one aspect, the decorative film substrate is provided as a pre-formed decorative film substrate. For example, the pre-formed decorative film substrate may include a surface discontinuity formed therein to reduce the stretching of the film substrate when molded in the molding apparatus.
In other aspects, the mold cavity forms a ridge on the composite shell to form the surface discontinuity. In further aspects, the ridge forms a step in the outer facing surface of the composite shell. In preferred form, the surface discontinuity further includes a ramp along at least a portion of the step to further enhance the wind noise reduction of the composite shell member.
These and other features, purposes, and advantages will be appreciated when the drawings are viewed in conjunction with the detailed description which follows.